1. Field of the Invention
The invention relates to an insulated glass assembly and, in particular, to core spacers separating glass panes.
2. Description of the Related Art
Insulating glass is usually made of at least two panes adhered together along their edges by a core spacer. In the prior art, there are several types of core spacers manufactured from synthetic foam which is soft and easily compressed. Exemplary is the spacer shown in U.S. Pat. No. 5,806,272 which was issued to Lafond on Sep. 15, 1998.
However, such foam core spacers have minimal stability because of their easy compressibility. Furthermore, such foam spacers are readily stretched longitudinally, thus allowing them to be deformed or broken apart before, during or after installation in a window frame.
Another disadvantage of foam core spacers is that they often interact chemically with hot melt butyl, thus causing a stain discoloration which is unacceptable aesthetically. Such a chemical reaction further frequently causes a variety of other problems, like a change in adhesion strength, a shrinkage of the foam spacer, or an expansion thereof. Whenever a shrinkage occurs, the spacer tends to pull away from the corners where the glass panes are joined together. Likewise, if an expansion occurs, the foam spacer becomes misshapen and appears unattractive.
A solid EPDM rubber core spacer is provided with a centrally positioned, nonstretchable cord made of fiberglass or similar material for imparting strength thereto. Furthermore, the EPDM rubber formulation is chemically compatible with hot melt butyl which is used as an adhesive and as a moisture vapor barrier. Although there are many differences between the hot melt butyls manufactured by different companies, it is important to formulate an EPDM rubber which ensures chemical compatibility.
A key advantage of the present invention is improved stability over foam core spacers when in compression during oven pressing, packing, shipping, and installing in windows. In each situation, the solid rubber core spacer undergoes significantly less compression than the foam of the prior art spacers.
Another advantage of the present invention is the incorporation of the fiberglass cord into the rubber core spacer so that no stretching of the spacer occurs during initial manufacture, spacer assembly, coiling of the spacer, and application of the finished spacer between two glass panes. Also, heating and cooling of the spacer does not result in any deformation or breakage of the spacer when in use because of the presence of the continuous nonstretchable fiberglass cord incorporated therein. Of course, in the real world, everything can be stretched to a breaking point if a powerful enough pulling force is exerted. In that sense, the fiberglass cord is nonstretchable under normal conditions of use.
A further advantage of the present invention is that the chemical composition of the EPDM rubber in the core spacer is such that it does not react, other than in a minimally inconsequential way, with hot melt butyl. Thus, this feature of the present invention prevents a chemical reaction that could cause a stain discoloration, a change of adhesion strength, shrinkage, expansion or any other disadvantage inherent in the prior art foam core spacers whenever a chemical reaction takes place.